The "Commons" refers to that part of Wikipedia called Wikimedia. As a genealogist or whatever, you should be very familiar with Wikipedia and Wikimedia. I am always somewhat amazed at the gulf between those who use the Web for research and those who are clueless about what is on the Internet at all. I hate to sound like an intellectual snob, but there are some resources on the Internet that are so basic that practically all of the users should be acquainted with them. Just in case, here is the description of the Wikimedia Commons:

Wikimedia Commons is a media file repository making available public domain and freely-licensed educational media content (images, sound and video clips) to everyone, in their own language. It acts as a common repository for the various projects of the Wikimedia Foundation, but you do not need to belong to one of those projects to use media hosted here. The repository is created and maintained not by paid archivists, but by volunteers. The scope of Commons is set out on the project scope pages.

Wikimedia Commons uses the same wiki-technology as Wikipedia and everyone can edit it. Unlike media files uploaded to other projects, files uploaded to Wikimedia Commons can be embedded on pages of all Wikimedia projects without the need to separately upload them there.

OK, a little tiny bit of history. Back a few years ago, there was a new website called Footnote.com. This was a website dedicated to putting documents online from the National Archives. It was a subscription site and was eventually purchased by Ancestry.com and converted to Fold3.com, hosting primarily military records. Somewhere in that process, the original idea of digitizing all of the holdings of the U.S. National Archives and Record Administration (NARA) got lost. There have been several NARA initiatives since then. For example, see Digitizing Historical Records from the National Historical Publications and Records Commission. Compared to such efforts such as the Australian National Library's online digitization effort called Trove.nla.gov.au, the efforts of the NARA are rather puny.

Here is an overview from the above post from Wikipedia about the project:

All of that is in the past, though. The Open Government Plan lays out what NARA wants to accomplish in the next two years; but as a general plan it suffers from a lack of specifics. The Signpost contacted McDevitt-Parks to learn what the inclusion of Wikipedia in this plan will mean for the site.

He told us that there is no quantitative target for a total number of image uploads, because NARA plans to upload all of its holdings to Commons. "The records we have uploaded so far contain some of the most high-value holdings (e.g. Ansel Adams, Mathew Brady, war posters)", he said. "However, we are not limiting ourselves to particular collections. Our approach has always been simply to upload as much as possible ... to make them as widely accessible to the public as possible."

This is one of those good news/bad news situations. The documents and images from NARA will become more available, but who will know they are there? As genealogists, we need to be aware that searching online is becoming more complicated and at the same time, more productive. But it helps if you keep abreast of the latest developments.